1. Field of the Invention
The present invention relates to an apparatus and method for processing substrates.
2. Description of the Related Art
The micro-pattern of a semiconductor integrated circuit is formed by etching a base film formed on a semiconductor wafer while using an organic high-molecular photoresist film obtained by exposure and development as a mask. The photoresist film used as the mask is removed from the surface of the semiconductor wafer after the etching process. The plasma etching apparatus can be mentioned as intending to carry out the etching process and the ashing apparatus can also be mentioned as intending to remove the photoresist film from the semiconductor wafer.
In the case of ultra-micro etching process, anisotropic etching is carried out at first and the isotropic etching is then carried out to remove those damages which are left on the surface of the semiconductor wafer by the ions of the anisotropic etching (see Page 75, Japanese Edition of Solid State Technology Published in March, 1985).
Conventionally, each of the anisotropic and the isotropic etching process and the ashing process was carried out using its own apparatus separated. The semiconductor wafer was carried in and out of each of these apparatuses while being carried among those sections at which the processes were carried out. However, the semiconductor wafer is contacted with atmosphere even when it is treated in a clean room, and oxide film is formed on the semiconductor wafer, furthermore, fine dust, impurities and moisture present in the atmosphere adhere to the treating surface of it. This caused the pattern on the substrate to have flaws. In addition, this made it difficult for the processes to be reproduced. When the semiconductor wafer is contacted with atmosphere while being carried from the section for the metal etching process to the other section for the resist etching process particularly in the case of the metal etching process, the residue of etching gas of the chlorine group contained in a micro-amount on the semiconductor wafer reacts with moisture in atmosphere to corrode the metal layer on the semiconductor wafer. Therefore, the semiconductor wafer could not be carried to a section for the next process unless the corroded metal layer was removed from the semiconductor wafer.
In order to solve this problem, apparatuses each provided with plural processing chambers and a passage shielded from atmosphere have been proposed so as to transport the semiconductor wafer between these chambers, as disclosed in Japanese Patent Disclosures Sho 62-69619 and 63-39676. However, each of these apparatuses is only a combination of those processing chambers each of which is used only to carry out one process. When the apparatus is made suitable for carrying out the recent processes, therefore, it becomes complicated and large-sized.